The present invention relates generally to an electromechanical structure of an electrical apparatus.
The size of portable electronic equipment in particular is being constantly reduced. This makes great demands, such as on the usability and durability of the various mechanical components in the equipment.
The physical components of electronic equipment are constructed to be simple and cheap, suitable for mass production, and easy to install on automated assembly lines. The components must additionally be designed so that various tolerance variations occurring in the components will not obstruct the installation or lessen the performance of the equipment.
Examples of small electronic equipment containing mechanically movable components are mobile terminals, CD stations, and CD players. The smallest mobile terminals are physically so tiny that when the loudspeaker is held to the ear, the microphone does not reach all the way to the user""s mouth without special arrangements. Mobile terminals of this kind can be enlarged with the aid of a telescope structure or with some other enlargement implementation, such as a collapsible structure. The force needed for the enlargement can be supplied by the user or obtained, for example, from a spring or a motor.
A mobile terminal including a body part and a grip part is described in the applicant""s earlier patent application FI20001008, which has not been published by the filing date of the present application.
FIG. 1a illustrates a structure for an extendable mobile terminal in a retracted configuration, where a relatively large portion of a body part 100 is located within a sleeve-like grip part 101. The grip part is mounted for longitudinal slidable movement between a retracted position and an extended position.
FIG. 1b illustrates the same telephone device in an extended configuration, where the body part has been moved into a longitudinal direction so that a larger portion thereof has been extended from the grip part.
The force needed for the opening movement is obtained from a torsion spring at the bottom of the grip part when the one-sided releasing switch is released. In another embodiment the force needed for the opening movement is obtained from a cogged rack with a gear wheel.
In the same application a solution is described whereby a spring barrel is used. The spring barrel, wherein a spring and a bi-directional damper are combined, is installed in the body part of the mobile terminal. When the mobile terminal is in the closed position, i.e. the body part is within the sleeve-like grip part the spring is compressed, i.e. the spring is in its stressed state. When the releasing latch between the body part and the grip part is released, the stored force of the spring pushes out the body part of the mobile terminal from the grip part into the extended or operative position. A damper slows down the mechanical movement of the body part in relation to the grip part. More specifically, the mechanical movement of the body part is controlled by a bi-directional damper, which absorbs a part of the spring force in order to prevent the body part from jumping out suddenly and noisily into the enlarged position. When the use of the mobile terminal has been terminated, the spring is reset, i.e. the body part is pushed down manually down into the grip part.
However, one drawback of the described solution is that the damper may not function in the normal manner at low temperatures (below 0xc2x0 C., for example). This is mainly due to the behavior of the damping oil of the damper housing. The oil solidifies and thus causes high torque and stress to the mechanical components of the spring barrel. This results in serious malfunction: the opening mechanism of the mobile terminal works very slowly, if at all.
In addition, should the damper not work or should it work very slowly, there is always the risk that the frustrated user will become impatient and try to open or close the equipment by force. In the worst case such behavior may break the mechanical components of the spring barrel.
Another drawback is that the movable part of the known extendable mobile terminals is not designed to be exchangeable. Thus, the movable part cannot be replaced with a new part having a different color, material, or shape.
In general, the opening mechanism in known solutions is still rather complex and expensive from the standpoint of manufacturing.
The invention especially concerns a two-part device comprising at least one spring module, whereby a flat belt-like spring is used to obtain for smooth movement for that component of the electronic equipment which is adapted to be movable.
It is an objective of the present invention to bring about a two-part device in such a way that the drawbacks mentioned above are eliminated. The intention is to implement the spring barrel module with the belt-like spring in such a way that its manufacture is economically advantageous, its installation is simple, and it tolerates various tolerance variations occurring in the components.
This objective is achieved in the manner described in the independent claim. Advantageous embodiments of the invention are defined in the dependent claims.
In the first embodiment of the invention, a spring barrel module consists of a first and a second cylindrical barrel, where the first barrel is adapted to rotate within the second barrel. The first barrel includes a spring and a damper, as well as a belt-like spring extending along the outer periphery. The first end of the belt-like spring is attached to the barrel and the second end to a slide element. The damper works in one direction only. Unidirectional damping is implemented by a one-way clutch.
The barrel can be delivered with a pre-tensioned belt-like spring. The outer barrel can be arranged to ensure that the belt-like spring can be kept pre-tensioned. This is especially important from the standpoint of mounting.
During use the second or outer barrel functions as a means controlling the belt-like spring and also protects the first barrel from dust and dirt.
In the second embodiment of the invention, the spring barrel module consists of one cylindrical barrel including a spring and a damper, as well as a belt-like spring extending along the outer periphery. The barrel is adapted to rotate within a hole in the body of the equipment in question.
When the movable part of the electronic equipment is in its closed position, the spring in the spring barrel module is in its stressed state. When the spring is released, the spring force is converted by a spring barrel adapted to rotate and by a belt-like spring into linear or rotary motion. In other words, the belt-like spring with the slide element slides along a groove in the equipment from its first position to its second position. Thus, that part of the electronic equipment which is adapted to move will open in a controlled and smooth manner.
When the movable part is closed, e.g. by pushing it manually, the belt-like spring with the slide element slides along the groove from the second position to the first position and the spring will reset.
It is especially advantageous to mount two spring barrels symmetrically on opposite sides of the equipment. When the electronic equipment is extended/retracted, the slide element with the belt slides along longitudinal grooves on the opposite side of the equipment. Thus, the system consisting of the barrel, the belt-like spring, and the slide element act as a bearing element between the body part and the movable part of the equipment.
The body part and the movable part can be fixed together in such a way that the movable part is easy to remove and replace with a new movable part if required.